What's with zombie mod escape maps

[geoxile]

They bring my FPS down to 20 sometimes especially on bigger servers.

Still, it's crazy, the engine is like 6 years old and it isn't even Source rev. 2, though I can see why.

Rig
PII x4 955
M4A79XTD EVO
4GB 1600DDR3 OCZ
8800GT 256mb (1280x1024 so it's fine).
Just the core parts.

DVD writer is generic
HDD, Caviar Green 5400RPM 500GB (almost same loading as blue imo, no apparent performance differences)

[OVRLOAD]

CSS does not use Multi-core support like other source games like Day of Defeat Source, it only users one core.

[arisaka]

^ because CSS doesn't run on the Orange Box engine.

I was also wondering...why is it that ZE maps are so popular? It's almost impossible to win even if you spawn at the very front. Makes for lots of rage and no pew pew.